ROOT_528-00b_version: tutorials/math/mathLaplace.C Source File

00001 // Test the TMath::LaplaceDist and TMath::LaplaceDistI functions
00002 // author: Anna Kreshuk
00003    
00004 #include "TMath.h"
00005 #include "TCanvas.h"
00006 #include "TF1.h"
00007 #include "TLegend.h"
00008 
00009 void mathLaplace(){
00010   TCanvas *c1=new TCanvas("c1", "TMath::LaplaceDist",600,800);
00011   c1->Divide(1, 2);
00012   TVirtualPad *pad1 = c1->cd(1);
00013   pad1->SetGrid();
00014   TF1 *flaplace = new TF1("flaplace", "TMath::LaplaceDist(x, [0], [1])", -10, 10);
00015   flaplace->SetParameters(0, 1);
00016   TF1 *f1 = flaplace->DrawCopy();
00017   f1->SetLineColor(kRed);
00018   f1->SetLineWidth(1);
00019   flaplace->SetParameters(0, 2);
00020   TF1 *f2 = flaplace->DrawCopy("same");
00021   f2->SetLineColor(kGreen);
00022   f2->SetLineWidth(1);
00023   flaplace->SetParameters(2, 1);
00024   TF1 *f3 = flaplace->DrawCopy("same");
00025   f3->SetLineColor(kBlue);
00026   f3->SetLineWidth(1);
00027   flaplace->SetParameters(2, 2);
00028   TF1 *f4 = flaplace->DrawCopy("same");
00029   f4->SetLineColor(kMagenta);
00030   f4->SetLineWidth(1);
00031   TLegend *legend1 = new TLegend(.7,.7,.9,.9);
00032   legend1->AddEntry(f1,"alpha=0 beta=1","l");
00033   legend1->AddEntry(f2,"alpha=0 beta=2","l");
00034   legend1->AddEntry(f3,"alpha=2 beta=1","l");
00035   legend1->AddEntry(f4,"alpha=2 beta=2","l");
00036   legend1->Draw();
00037 
00038   TVirtualPad *pad2 = c1->cd(2);
00039   pad2->SetGrid();
00040   TF1 *flaplacei=new TF1("flaplacei", "TMath::LaplaceDistI(x, [0], [1])", -10, 10);
00041   flaplacei->SetParameters(0, 1);
00042   TF1 *g1=flaplacei->DrawCopy();
00043   g1->SetLineColor(kRed);
00044   g1->SetLineWidth(1);
00045   flaplacei->SetParameters(0, 2);
00046   TF1 *g2=flaplacei->DrawCopy("same");
00047   g2->SetLineColor(kGreen);
00048   g2->SetLineWidth(1);
00049   flaplacei->SetParameters(2, 1);
00050   TF1 *g3=flaplacei->DrawCopy("same");
00051   g3->SetLineColor(kBlue);
00052   g3->SetLineWidth(1);
00053   flaplacei->SetParameters(2, 2);
00054   TF1 *g4=flaplacei->DrawCopy("same");
00055   g4->SetLineColor(kMagenta);
00056   g4->SetLineWidth(1);
00057 
00058   TLegend *legend2 = new TLegend(.7,.15,0.9,.35);
00059   legend2->AddEntry(f1,"alpha=0 beta=1","l");
00060   legend2->AddEntry(f2,"alpha=0 beta=2","l");
00061   legend2->AddEntry(f3,"alpha=2 beta=1","l");
00062   legend2->AddEntry(f4,"alpha=2 beta=2","l");
00063   legend2->Draw();
00064   c1->cd();
00065 }